Department of Cellular and Molecular Biophysics, Max Planck Institute for Biochemistry, Martinsried, Munich, Germany.
Graduate School for Quantitative Biosciences (QBM), Ludwig-Maximillians-University, Munich, Germany.
Sci Rep. 2020 Jun 26;10(1):10447. doi: 10.1038/s41598-020-67224-x.
As one of the key elements in bacterial cell division, the cytoskeletal protein FtsZ appears to be highly involved in circumferential treadmilling along the inner membrane, yielding circular vortices when transferred to flat membranes. However, it remains unclear how a membrane-targeted protein can produce these dynamics. Here, we dissect the roles of membrane binding, GTPase activity, and the unstructured C-terminal linker on the treadmilling of a chimera FtsZ protein through in vitro reconstitution of different FtsZ-YFP-mts variants on supported membranes. In summary, our results suggest substantial robustness of dynamic vortex formation, where only significant mutations, resulting in abolished membrane binding or compromised lateral interactions, are detrimental for the generation of treadmilling rings. In addition to GTPase activity, which directly affects treadmilling dynamics, we found a striking correlation of membrane binding with treadmilling speed as a result of changing the MTS on our chimera proteins. This discovery leads to the hypothesis that the in vivo existence of two alternative tether proteins for FtsZ could be a mechanism for controlling FtsZ treadmilling.
作为细菌细胞分裂的关键要素之一，细胞骨架蛋白 FtsZ 似乎高度参与在内膜上的周向行走，当转移到平面膜上时会产生圆形涡流。然而，目前尚不清楚膜靶向蛋白如何产生这些动力学。在这里，我们通过在支持膜上体外重建不同的 FtsZ-YFP-mts 变体，剖析了膜结合、GTP 酶活性以及无规卷曲 C 末端接头对嵌合 FtsZ 蛋白行走的作用。总之，我们的结果表明，动态涡旋形成具有很大的稳健性，只有导致膜结合被废除或横向相互作用受损的显著突变，才会对行走环的产生产生不利影响。除了直接影响行走动力学的 GTP 酶活性外，我们还发现，由于改变我们嵌合蛋白上的 MTS，膜结合与行走速度之间存在惊人的相关性。这一发现导致了这样一种假设，即 FtsZ 两种替代的系绳蛋白的体内存在可能是控制 FtsZ 行走的一种机制。
